It has been known that hydrogel particles, in which dispersed particles including various kinds of functional materials are distributed, are applicable to cosmetic products, drugs, quasi drugs, and other products.
Patent Document 1, for example, discloses a method for producing such hydrogel particles in which a dispersion, containing an oil component dispersed in an aqueous component solution of dissolved gel agent forming a non-crosslinked hydrogel, is prepared and sprayed into a gas phase to form droplets, which are then cooled and allowed to solidify.
Patent Document 2 discloses preparing an O/W/O emulsion by dispersing, in an external oil phase, an O/W emulsion produced from an internal oil phase and an aqueous phase including a hydrophilic polymer gel agent, and then cooling the O/W/O emulsion to solidify the aqueous phase.
Meanwhile, Patent Document 3 discloses a method of making a thickener including the step of preparing an aqueous solution in which a hydrophilic compound with a gelling capability is dissolved in either water or an aqueous component, leaving it to stand still and cool to form a gel, and then pulverizing the gel.